(define (make-vect x y) (cons x y)) 

(define (xcor-vect vec) (car vec)) 

(define (ycor-vect vec) (cdr vec)) 

(define (eq-vect? v1 v2) 
  (and (= (xcor-vect v1) (xcor-vect v2)) 
       (= (ycor-vect v1) (ycor-vect v2)))) 

(define (add-vect v1 v2) 
  (make-vect (+ (xcor-vect v1) (xcor-vect v2)) 
             (+ (ycor-vect v1) (ycor-vect v2)))) 

(define (sub-vect v1 v2) 
  (make-vect (- (xcor-vect v1) (xcor-vect v2)) 
             (- (ycor-vect v1) (ycor-vect v2)))) 

(define (scale-vect s vec) 
  (make-vect (* s (xcor-vect vec)) 
             (* s (ycor-vect vec))))
